1. Field of the Invention
The present invention relates to a communication method based on transmission control protocol (TCP), and more particularly, to a communication method based on TCP and a mobile communication terminal for performing the method, where an initial setting value of a congestion window is set according to a communication situation of a communication network to more efficiently use uncongested bandwidth of a communication network.
2. Discussion of the Background
Generally, the transmission control protocol (TCP) is a protocol used to reliably transmit packet data by supplementing repeated transmissions, reducing loss and disordering of internet protocol (IP) packets, and controlling communications so packet data can be transmitted using a sliding window scheme and a congestion control scheme.
The congestion control scheme in TCP allows a terminal to set a volume of transmittable packets without loss caused by congestion according to the available capacity of a communication network. Further, the TCP couples algorithms such as additive increase/multiplicative decrease, slow start, fast retransmit, and fast recovery to control the volume of packets being transmitted by the sender, thus leading to control of the congestion situation.
In the slow start algorithm, the sender uses the size of an advertised window (“AWND”) which is informed by a receiver and another window called a congestion window (“CWND”), wherein the CWND is initialized as one segment when a new communication access is established. Each time the sender receives an ACK (acknowledge) message that data was transmitted successfully according to a current CWND value, it increases the CWND value by one segment, thereby continuously increasing the CWND according to successful data transmission. Initially, however, the sender transmits the minimum value of the CWND and AWND. Such a slow start algorithm uses the CWND anytime a communication access is initiated on the basis of TCP and if an ACK message time out occurs.
Previously, when a communication was carried out by applying the slow start algorithm of TCP to establish a data service for a mobile communication terminal, the initial value of the CWND was established as a fixed value of one (1), and increased from the initial value according to the slow start algorithm. However, this created a lengthy process leading up the point where a mobile communication terminal could more fully use the available bandwidth of a communication network according to the congestion level or communication situation.